Field of the Invention
The invention relates to a machine tool for machining a work with a tool. In particular, the invention relates to a machine tool that includes a saddle, which is movable along a first axis, and a table, which is disposed on the saddle and movable along a second axis, wherein the first axis and the second axis are orthogonal to each other.
Description of Related Art
The known machine tool has a saddle that is carried by a bed and a table that is carried by the saddle. The saddle is movable along one of an X-axis and a Y-axis, which are orthogonal to each other, while the table is movable along the other axis. In this type of machine tool, guide rails are installed on the saddle, and the table is moved along the guide rails. However, due to the straightness error of the guide rails, undesirable yawing may occur on the table. Therefore, installation of the guide rails requires considerable expertise, and it is considered difficult to use long guide rails on this type of machine tool.
Patent Document 1 discloses disposing an additional rotary table on an XY table. The additional rotary table includes a drive unit. Although the additional rotary table can correct an angle error caused by yawing, it also complicates the structure of the machine. Patent Document 1 also discloses a method for detecting a yawing amount and correcting a position error in each direction of the X and Y axes.